Excavator



May 11,1926. 1 1,583,811

G. T. STUBBLEBINE EXCAVATOR Filed Sept. 18 1925 3 Sheets-Sheet 1 May 11 1926.

a. T. STUBBLEBINE EXCAYATOR Filed Sept. 18 1925 3 Sheets- Sheet 2 May 11 192 1,583,811

a. T. STUBBLEBINE ExcAvuoR Filed Sept. 18 1925 3 Sheets-Sheet 3 Patented May 11, 1926.

n nirrn STATES GEORGE T. STUBBLEBINE, OF BUFFALO, NEW YORK.

nxoAvATon.

Application filed September 18,1925. Serial Nb. 57,109.

This invention relates to an excavator or shovelling machine whereby earth, rock and similar material is picked up by means of a scoop or bucket and transferred from one place to another. In machines of this character as heretofore constructed the door which closes the outlet of the body of the scoop or bucket was held in its closed or operative position by means of a locking device whichwas released'by manual pull thereof. This is objectionable not only because it requires an extra man for taking care of the dumping of the bucket or scoop but it is also objectionable because of the liability of accidentally tripping the locking mechanism and discharging the contents of the bucket or scoop prematurely at places where it is not desired.

It is the object of this invention to pro vide an operative mechanism which is operatively connected with the locking device which holds the door of the scoop in its closed position and which can be controlled by the same operator who controls the filling operation of the scoop and the lifting and lateral movement of the same, which mechanism is so constructed that it will not release the outlet door of the bucket accidentally upon striking an obstruction.

\Vith this end in view this operating mechanism for the locking device of the door which controls the outlet of the scoop or bucket consists generally of a motor, preferably of the electric type, which is operatively connected with the door locking device of the scoop and which is controlled by'an electric switch arranged adjacent to the attendant who controls the filling and transporting operation of the scoop, this mechanism in its preferred construction being so organized that if the attendant should through over sight hold the electric circuit closed longer than necessary, such circuit will be automatically opened when the scoop door is in its fully opened or discharging position, thereby preventing any injury to the motor and associated parts by straining them or by burning out the winding of the motor.

In the accompanying drawings Figure 1, is a side elevation of the front part of an excavator or shovelling machine equipped with a practical form of my invention, the electric circuits ofthe same being it or bucket showing the bottom or outlet door;

thereof in its open or dumping position.

Figure 5, is a vertical transverse section on line 55,'Fig. 2 looking forwardly.

Figure 6, is aframentary top plan view of the electric motor which releases the locking mechanism for permitting the bottom or discharge door of the scoop to move into its open position.

Figure 7 is a vertical transversesection, on an enlarged scale, taken on line 77, Fig.

Similar characters'of reference indicate like parts throughout'the several views.

My invention is applicable to excavators or shovelling machines of various kinds and intended for different classes of work and the machine which is shown in the drawings is, therefore, intended to merely serve as an i I example of one inwhich my invention can be used advantageously;

The part of the excavator which is shown in the'drawmgs in order to illustrate the application of my invention consists generala carriage or truck havlng a main frame or body 10 which 1s supported upon' ly of the ground by means of wheels 11 so that the machine can be transported on the ground from one place to another, a boom 12 arranged in front of the truck and pivotally connected at its rear end by means of a universal coupling or swivel 13 with the front part of the truck body so that the boom can be raised and also moved hor izontally into diiferent positions. A scoop orbucket is movable lengthwise of the boom and capable of rising and falling as well as moving horizontally therewith and consists generally of a body lt having an inlet at its front end and an outlet'in its bottom,

and a vertically swinging door or bottom 15 which is pivotally mounted on the body of the scoop so as to permit of either closing or opening the outlet of the scoop. In the preferred construction the boom consists of two I-beams 16, 16 which are arranged side by side and suitably connected so that they form a ratchet structure and face with two' of their concave sides outwardly so that these sides together form a grooved guideway 17 which extends lengthwise of the boom. The scoop is mounted on the boom so as to move lengthwise on this guideway, this being preferably effected by means of two'longitudinal supporting bars arranged on opposite sides'of the boom and connected at their front ends by a yoke 19 with the front bucketor scoop for moving the same forwardly which transmitting device in the present case consists of a hauling or drag line 22 secured to the rear wall of the scoop body and. passing from thence forwardly and upwardly around a guide sheave 23 mounted on the front part of the boom thence rearwardly and upwardly around an intermediate guide sheave 2 f mounted on the rear part of the boom and thence up- Wardly andrearwardly over a guide sheave 25 on the chassis of the truck and to the drum of the power operated hoisting mechanism. Upon winding the drag line upon this drum of the hoisting mechanism the scoop is drawn forwardly for the purpose of causing the same to pick up a load of material after which the boom is raised through the medium of a hoisting mechanism and also moved laterally preparatory to depositing the load of the material in the scoop either into a wagon or at one side of the excavation. This lifting of the boom is effected by means which comprise a hoisting line 26 suitably connected with the chassis and with the hoisting engine and passing around a guide pulley 27 on the front part of the boom. The turning of the boom is also effected by means of power derived from the hoisting engine which is transmitted to the boom by means which comprise a horizontally rotating swinging wheel 28, connected with the boom and a turning line 29 passing around the wheel 28 and operatively connected with the hoisting engine.

The bottom or door 15 of the scoop is connected near its front end with the side walls of the scoop body by means of pivot bolts 30 or other suitable means and at its front end the bottom is provided with digging same into the scoop body above the bottomor door thereof. This door closes the out let in the bottom of this scoop body while the scoop is being loaded and the charge is.

being lifted and transported. While the scoop is thus picking up a load its bottom or door is held shut, by means ofa locking device which latter is released when 'the bucket is in the top position for unloading so that the bottom or door drops by gravity and permits the material to discharge downwardly through the outlet of the bucket body. This locking device is so constructed that when the bucket or scoop is again lowered into its operative position the door or bottom thereof will be automatically locked in its closed position. The forward motion of the scoop is effected by power but the return movement of the same is effected by gravity inasmuch as the ,weight of the bucket is utilized to slide the same downwardly and backwardly on the boom while the latter is in an inclined position."

Although Various forms of locking devices may be employed that shown in the drawings is now in common use and is constructed as follows The numeral 32 represents a latch or catch which swings in vertical plane lengthwise of the bucket and is arranged in rear of the body and pivotally connected with the rear wall thereof at its upper end by means of a horizontal transverse pivot 33. At is lower end this catch is provided with a. forwardly projecting hook 34 which is adapted to engage underneath lug or keeper at the rear end of the bucket bottom or door when the latter is in its closed position, as shown in 1 and 3. This catch is yieldingly held in engagement with the keeper 35 by means of a spring 36 secured to the rear wall of the bucket body and engaging with the rear side of the latch or catch, as shown in Fig. 5. Disenp'agement of the catch from the keeper 30 for permitting the bucket bottom to drop by gravity is effected by means of a releasing cam 37 which is rotatable in a vertical plane and adapted to engage with the front side of the catch. When the low part of this releasing cam faces the catch as shown by dotted lines in Fig. 3, the catch is permitted to engage the keeper and hold the bucket bottom or door shut, but when swinging this cam backwardly so that its high part engages with the catch then the catch is disengaged from the keeper and permits the bucket bottom to drop, as shown in Fig. i. This releasing cam is mounted on a rock shaft 9 which is journaled horizontally and transversely in suitable bearings on the rear side of the rear wall of the bucket body, as best shown in Fig. 5, and the same is turned .in the hands keeper of thebucket bottom is elfected by means of a rock arm 39projecting upwardly from one end of this shaft and adapted to engage with a stop 40 on the upper part of the bucket body for arresting the movement of this arm when the same is in an" upright position and the cam'37 is turned so as to permit thecatch to interlock with the keeper on the bottom, as shown in Fig. 3. i

Heretofore this bucket bottom locking device was manipulated by means ofa rope having one end attached to this rock arm 39 while the other end was of an attendant whose sole duty was to pull this line and release the loadwhen the bucket had been carried to the proper position. The attendant who controlled the dumping of this bucket was employed in addition to the engineer who controlled and directed the movement ot the bucket over the ground for picking up a load and then carrying thesame to the place of deposit so that in all cases at least two men were necessary in order to look after the operation of digging or shovelling the material and then depositing the same where required. Owing to the necessity of employing a line from the rock arm 39 to the attendant whose duty consisted of discharging the contents of the bucket at the proper place it frequently occurred that this pull line would become fouled with some other part of the machine, thereby causing a discharge of a bucket load of material at places where it was not desired and thus involving extra expense and trouble in again clearing up matters.

Thepresent invention contemplates operating the trip lever or arm 39 of the locking mechanism bypower operated means which are under the control of the same attendant who directs the movements of the scoop which power operated mechanism is so organized that there is little likelihood of the load of the scoop being dumped accidently. In its preferred construction the present improved rock operating device is constructed as follows The numeral 4L1 represents an electric motor which is mounted on the body of the scoop so as to be movable therewith. In the preferred construction this motor is arranged in rear of the body of the scoop and mounted on a bracket 42 which projects rearwart ly from the rear hangers 20 forming part of the carriage whereby the scoop is movably mounted upon the boom This electric motor is provided with a driving shaft 43 and on one end of this shaft the same is provided with a drum or winding wheel 44, the periphery 45 of which pref-- erably has the form of a cam or snail. A releasing line 46 having preferably the form t of a chain has one end connected with the a low part ofthis releasing 'camwhile the other end is connected with the upper end of the trip arm 39. Upon energizing the motor the cam ttwill be turned in the direction of the arrow associated with the cam in Fig. 3, whereby the pull line 46 will be wound up on the cam andcaused to move the trip arm 39 .backwardly so that the releasing cam 37 will disengage the catch 82- from the keeper 35 of the scoop bottom and permitthe latter, to drop by gravity, During the forward rotation of this pulling cam 44: thepullline 4J6 gradually engages successively with parts of the periphery of this cam which are increasing 1y further from the axis of the same so that the first pullingelfectupon the trip arm 39 is very powerful and thereafter the speed of the winding up action of the line 46 on this cam44 is gradually increased so that a very quick and prompt releasing of the scoop door is produced. Upon again closing the scoop dooror bottom the'triplever or arm 39 is again swung forwardly by the release of the spring 38 whereby the pull line 46 is again unwound from the cam drum wheel 44 and'the latter is turned back to its initial or starting position. The electric current for operating theelectric motor 41 may be supplied from any suitable source but preferably from a storage battery 47' which is mounted on any suitable part of the excavator and has one side grounded as shown at 48. The other side of this storage battery is connected with one pole of an electric generator which is also grounded on the opposite side as shown at 49' which generator may be used for vari ous purposes including that of charging the storage battery 47 when required. The current is conducted from thisstorage battery bya line 50 to a switch 51 arranged on the frame or chassis of the truck adjacent to where the attendant stands who usually controls the mechanism which moves the boom vertically and horizontally and also moves the digging scoop or bucket lengthwise of the boom. This switch has one of its con tacts connected with one side of the electric motor tl while the opposite side of this is grounded in any suitable way on some metallic part of the machine.- The electric circuit from the switch 51 to the electric motor 4-1 includes means which permit the bucket or scoop to travel lengthwise of the boom and still permit of making and break ing the electric circuit through the motor 41; For this purpose a metallic trolley wire 2 is provided which is arranged lengthwise over, the boom and connected at its. opposite ends with brackets 53, 54 which are arran ed on the boom which brackets are, however, insulated from the trolley wire 52 by means oi insulated couplings 55, 56 as shown in Figs. 1 and 2. On one 01 the longitudinal bars 18 of the bucket carriage is mounted an upwardly projecting trolley which preterablyconsists of an arm 57 pivoted by means of a horizontally transverse pin 58 to the upper part otone of the bars 18 and provided at its upper end with a trolley wheel 59 which connects with the top of the trolley wire 52, as shown in Figs. 1, 2 and 5. This trolley arm is composed of upper and lower metal sections which are connected by an insulated joint so as to confine the current to the upper part of this trolley, this upper part being connected by a wiretl with one end or pole of the electric motor 41.

The wheel 59 of the trolley is yieldingly held in engagement with the trolley wire 52 by means of a spring 8 connecting the trolley arm or pull with an adjacent stationary part of the carriage which supports the bucket body, for instance one of the longitudinal bars 18, as shown in Fig. 1.

Due to this construction an electric connection is provided between the electric motor 41 and the source of current in all positions of the bucket lengthwise of the boom on which the same is capable of moving back and forth. 1

V hile the bucket is being moved forwardly over the ground or the material which is to be picked up the switch 51 is lett open so that the motor 41 is tie-energized and the catch 32 of the locking device holds the bottom or door of the scoop in its closed position. After the scoop has been thus loaded with material and the same has been raised and also moved horizontally in either direction to: the place where the material is to be deposited then the operator or attendant who also controls the movement of the bucket closes the manually operated switch 51 either by stepping on the same or manipulating it by hand, whereby the circuit is closed tl'n'ough the motor 41 and the latter is caused to give a quick powerful turn to its shaft 43, thereby turning the winding cam 44 and producing a pull on the line 46 which will cause the releasing cam 37 to disengage the catch 32 from the keeper and the bucket door and thereby permit the latter to drop by gravity and discharge its load through the outlet in the bottom of the body. As soon as the operator lets go the switch 51 the spring 88 again turns the releasing cam shaft 9 backwardly cau ing a forward pull on the line or chain 46 whereby the pulling cam 44 and the armature of the motor 41 are again turned backwardly to their initialposition.

lhe closing'of the circuit of the motor 41 can be effected without any exertion on the part of the man who generally attends to the loading and transporting movement of the bucket and therefore enables him to-take care of both the loading and transportingas well as discharging of the load from the bucket whereby the services of an ez-itra attendant and the cost incident to employing a man for the sole purpose of discharging the bucket is avoided. Due to the absence of any hand operated lines for actuating the lock ng dcvicethe liability of interference with such lines and causing the bucket to discharge accidentally is wholly eliminated as well as the nuisance and extra work which would be involved in such accidentaldischarge of the bucket.

In the absence or" any provision to avoid it the attendant might at times keep the circuit of the motorclosed too long after the work of opening the bucket bottom has been efiected and thereby cause either the motor winding to be burned out or unnecessary strain produced upon the pull chain 46 and .associated .parts which might be damaged thereby. Means are therefore provided whereby the breaking of the electric current through the motor 41-is effected automatically the instant that the pull line 46 has been drawn backwardly and disengaged the catch 32 from the keep-er otthe bucket body.. This result may be obtained by various means but in the preferred construction shown in the drawings this is accomplished by means of an electric switch having two co-operating contacts 62and 63, the former being relatively stationary and mounted on the bracket 42 which carries the motor and the latter being mounted on .a vertical movable throwout arm 64 which is pivoted at one end on the bracket 42 and provided at its other end with a roller 5 which rides on the cam or snail shape periphery oi? the winding wheel or drum 44, as shown in Figs. 1-6. When the pull line 46 is unwound from the winding drum 44 and the catch 82 is in its locked position the roller 65 oi the throwout arm engages with the low part of the peripheral face 45 of the winding cam, as shown in Fig. 3, whereby the movable contact 63 ot the automatic throwout switch engages with the stationary companion contact 62, as shown in Fig. 7 whereby the circuit of the electric motor 41 at this point is closed. If, therefore, the attendant closes the circuit of the electric motor by means of the switch 51 this motor will become energized, turn the winding wheel 44 and release the catch 32 of the locking mechanism from the bucket door or bottom. If, however, the attendant retains the switch 51 in a closed position after the locking device of'the bucket has been operated and its bottom released then the winding wheel 44 during the last portion of its rotation causes the highest part of its cam or snail surface to lift the free end of the throwout arm Gand disengage the movable contact 63 from the relatively stationary contact 62 and thereby automatically arrest the forward rotation of the motor shaft 43. By this means undue strain upon the parts which release the bucket bot- Iom is avoided and liability of burning out the motor which would be liable to occur if the current were permitted to flow through the same an undue length of time is prevented. lVhen the cam wheel l is again turned backwardly the weight of the throwout arm 64% follows the gradual receding cam surface 45 so that this'arm upon reaching its lowermost position again li'lOVGS the movable contact 68 into engagement with the fixed contact 62 and ire-establishes the circnit at this point so as to permit the motor to be again operated by the attendant closing the circuit through the medium of the switch 51.

As a whole this mechanism for control- J ling the operation of the bucket locking mechanism is ve-ry'simple, durable and inexpensive in construction, the same is not liable to get out of order, it can be installed on excavators of various types now in general use without requiring any radical change in the same, and owing to the fact -that it permits of dispensing with the service of an extra man to attend to the dumpmg of the bucket and that accidental dumping of the bucket is also prevented, a considerable increase in the output of an excavator is obtainable thereby materially reducing the cost of this work.

I claim as my invention 1. An excavator comprising a guideway, a scoop movable back and forth on said guideway and having a body provided with an outlet, a door for closing said out-let, and a locking device for holding said door in its closed position, and means for operating said locking device to release said door comprising an electric motor mounted on said body, and operatively connected with said locking device.

2. An excavator comprising a guideway, a scoop movable back and forth on said guideway, and having a body provided with an outlet, a door for closing said outlet, and a locking device for holding said door in its closed position, and means for operating said lockingdevice to release said door comprising an electric motor mounted on said body and operatively connected with said locking device and a switch for closing the circuit of said motor.

3. An excavator comprising a guideway,

a scoop movable back and forth on said guideway and having a body provided with an outlet, a door for closing said outlet, and a locking device for holding said door in its closed position, and means foropcrating said locking device to release said door comprising an electric motor mounted on saidbody andoperatively connected with said locking device, a switch for closing the c. cuit of said motor, and an automatic switch for opening the circuit of'said motor.

4-. An excavator comprising a guideway, a scoop movable back and forth on said guideway and having a body provided with an outlet, a door for closing said outlet,'and a locking device for holding said door in its closed position, and means for operating said locking device to release said door comprising an electric motor mounted on said body, and operatively connected with said locking device and means for conducting an electric current to said motor while the scoop is in different places on saidguideway.

5. An excavator comprising aguidoway, a scoop movable back and forth on said guideway and having a body provided with an outlet, -a door for closing said outlet, and a lockingdevice for holding said door in its closed position, and means for op erating said locking device to release said door comprising an electric motor mounted on said body, and operatively connected with said locking device and means for conducting an electric current to said motor while the scoop is in different places on said guideway comprising a trolley wire arranged lengthwise of said guideway, and a trolley mounted on said body and connected in circuit with said motor and engaging with saidtrolley wire.

v6. An excavator comprising a guideway, a scoop movable back and forth on said guideway and having a body provided with an outlet, a door for closing said outlet, and a locking device for holding said door in its closed position and means for operating said locking device to release said door comprising an electric motor mounted on said body and having a shaft, a cam wheel mounted on said shaft, and a pull line connected with. said locking device and said cam wheel.

7. An excavator comprising a guideway, a scoop movable back and forth 011 said guideway and having a body provided with an outlet, a door for closing said outlet, and a locking device for holding said door in its closed position, and means "for operating said locking device to release saiddoor adapted to be wound on the periphery of comprising an electric motor mounted on said body and having a shaft, a cam wheel mounted on said shaft, a pull line connected with said locking device and adapted 'to be wound on the periphery of said cam Wheel,

a switch having co-operating contacts arranged in circuit with said motor, and a rock lever riding on the periphery of said 021111 and carrying one of said contacts.

'8. An excavator comprising a guideway, '2 scoop movable back and forth on said guideway and having a body provided with an outlet, a door for closing, said outlet, and

a locking device for holding said'door in its closed position, and means for operating said locking device to release said door comprising an GlQCtIlO lDOtOI"IDQUHtGCl on said body, a cam Wlicel driven by said motor, and an electric switch actuated by ssidcain Wheel and controlling said inotor.

GEORGE T. STUBBLEBINE. 

